List without duplicates flutter code example
Example 1: dart unique list
var ids = [1, 4, 4, 4, 5, 6, 6];
var distinctIds = ids.toSet().toList();
Example 2: remove duplicates in json in flutter
var json = jsonDecode(yourJsonAsString);
var records = mutableListFrom(json["records"]);
var distinct = records.distinctBy((it) => it["Title"]);